1. watch

2. wasn't

3. has gone

4. has worked

5. has taken

6. has played

11. hasn't gone

1. foreign languages

2. monopoly 

3. fragile

4. doing gardening

5. making models

6. egg-shells

7. making pottery

8. carving
9. result

10. ice-skating

1. In spite of his broken leg, he managed to get out the car

2. I've never met anyone more punctual than your brother

3. You didn't remember to post the letter, did you?

4. Nam and his family had a trip to their home village for two days

5. I wish I had a laptop now because it's very necessary for me

1. He wishes he worked in a comfortable room

2. A new plan can be shown by my mother at the company

3. She hasn't seen him for two days

4. My sister is looking forward to hearing from her close friend

1. This is the first time I've ever been in London

2. I have played piano since I was six

3. They always play badminton on Tuesday

4. It's time you left home

5. She is not sastisfied with what she is doing

6. They gave up spending too much time on waching TV

7. They got ready for their lesson for the exam very well

8. He used to write home every week

9. We have written to each other for three years

10. It took us three hours to finish the exam

ở trên là \(\left(a-b\right)^2\ge0\)

Ta có \(a^2+b^2\ge2ab\Leftrightarrow a^2-2ab+b^2\ge0\Leftrightarrow\left(a+b\right)^2\ge0\) ( luôn đúng )

Tương tự, \(a^2+b^2+c^2\ge ab+bc+ac\)

\(\Leftrightarrow a^2+b^2+c^2-ab-bc-ac\ge0\)

\(\Leftrightarrow2a^2+2b^2+2c^2-2ab-2bc-2ac\ge0\)

\(\Leftrightarrow\left(a^2-2ab+b^2\right)+\left(b^2-2bc+c^2\right)+\left(c^2-2ac+a^2\right)\ge0\)

\(\Leftrightarrow\left(a-b\right)^2+\left(b-c\right)^2+\left(c-a\right)^2\ge0\) ( luôn đúng )

11. enjoyed

12. didn't want 

1. persuasively

2. corresponded

3. religion

4. friendship

5. disappointed

6. unequally

26. teach → teaching

27. enjoy → enjoys

28. will → ∅

29. painting → collecting

30. importance → important